First it was Rajon Rondo and now Jared Sullinger. The Celtics rookie will miss the rest of the season after surgery Friday to repair his chronic back injury.

The team announced that Sullinger underwent successful lumbar disc surgery at the New England Baptist Hospital. Surgery was performed by the medical staff under the direction of Celtics Team Physician, Dr. Brian McKeon. The Celtics also announced Sullinger is expected to be ready in time for training camp for the 2013-14 season.

Sullinger aggravated his back in the opening minutes of Wednesday’s win over Sacramento. The news came just four hours before the Celtics host the Orlando Magic at TD Garden.

When Sullinger went down four minutes into Wednesday’s game, fears were raised that this was a recurrence of back problems that forced him to miss nearly half of his final (sophomore) year at Ohio State and fall to 21st overall in the NBA draft last June. Celtics president of basketball operations Danny Aingeconfirmed those fears Friday. Head coach Doc Rivers said before Wednesday’s game that Sullinger was playing at a “top 5” draft pick level.

The numbers support that. He averaged 7.0 points and 7.2 rebounds in 15 games in January, and finishes the season with averages of 6.0 points and 5.9 rebounds per game. He had four double-doubles, including three in January. Sullinger spent most of the season as one of the best weapons off the Boston bench but Rivers rewarded Sullinger for his development and play by moving him into the starting lineup last Sunday for the game against the Heat.

Sullinger started Wednesday and grabbed one rebound but did not score before coming out with what was first diagnosed with back spasms. He received ice treatment in the locker room and the team was hopeful he could return. Just before halftime, the team revised the prognosis and announced he would not be returning.

The story was first reported by Adrian Wojnarowski of Yahoo Sports Friday afternoon.

Celtics rookie Jared Sullinger will miss the rest of the season with a back injury, league sources tell Y! Sports. He will need surgery.